A bad transmount or transfer case .
Slipping , slow to move, won't move, shudder, chatter, all are damaging to transmission.
Failed radiator transmission cooler.
There can be several things that will cause your 2000 Dodge Durango transmission to slip into reverse. A malfunctioning slave valve can cause this to happen.
A bad transmission.
faulty speed sensor in the transmission
try a bottle or rear end friction modifer if the problem is torque converter shudder it sould quit in a matter of miles most people mistake torque converter shudder for a eng miss feels the same
dirty tranny fluid
Replace the torque converter.
No
Transmission mount
the overdrive sencer
There should be no way for transmission fluid to be getting into a cylinder on a DOdge 360.